Plate 27 

 Smittina obicullata, new species 



Figure A: An old zooecium. Ovicell is partly overgrown by a secondary calcified laver 

 which encroaches first laterally, then more distally across the ovicell. Higher elevation of 

 suboral avicularium above the rest of frontal surface is difficult to show in a frontal view. 

 From Station 234. Drawn to the scale between this figure and figure F. 



Figure B: Freehand view of an ovicelled zooecium, from the side. The globose, porous 

 ovicell at left is being encroached upon at the sides by secondary calcification. Collared 

 peristome projects forward and upward, with sinus forming a wide gap in it frontall)^ above 

 the avicularium. Avicularium is on a small plateau of varying elevation above the rest of 

 porous front. Mandibular area approximately parallel with the zooecial base. 



Figure C: Six zooecia of holotype colony from Station 190 showing four zooecial possi- 

 bilities or conditions: zooecia with or without ovicells or avicularia. Peristome variable but 

 above the avicularium. Drawn to scale at left. 



Figure D: An operculum with two lateral sclerites for muscle attachment. Fmm 

 Station 226. Same scale as figures A and F. 



Figure E: Mandible. Darker parts are more heavily chitinized than paler parts. Man- 

 dibular pivot shown in white across top. From Station 226. Drawn to the scale directly 

 above. 



Figure F: Oblique view of an operculum and one bundle of muscle fibers attached to the 

 sclerite region. Second muscle bundle is broken oft' and its stub is at lower right. From 

 Station 226. Drawn to the scale at left. 



Figure G: Bilaminate holotype colony. Drawn to the scale at left. 



Figure H: Primary orifice and unfinished ovicell of a young holotype zoid. Same scale 

 as figure J. 



Figure I: Secondary orifice of a young holotype zoid. Here the peristomial wings nearly 

 touch above the sinus (cf. sinus in figures A, J-L). Same scale as figure J. 



Figure J: Old zooecium with worn-down peristome, from same calcined colony as figure 

 A; tipped to show primary orifice, lyrula and cardelles. Drawn to the scale below. 



Figure K: Ovicelled zooecium showing increasing secondary calcification at lower 

 corner and distal surface of the ovicell. Zoid and ovicell are in a colony concavity so ovicell 

 frontal seems proportionately much shorter than those of figures A and C. From holotype. 

 Drawn to scale above. 



Figure L: Zoid with unusually tall peristomial wings and a mandible in place on avicu- 

 larium. From holotype. Same scale as figure J. 



